Prophy angle

ABSTRACT

The present invention provides a dental prophylaxis angle that includes a singular housing, a drive shaft, a rotor, and a collar. The housing may define a first bore, a second bore in communication with the first bore at a substantial angle thereto, and a third bore coaxial with the second bore. The drive shaft is positionable in the first bore, and the drive shaft may include a post, which may define a spherical depression. The rotor is positionable in the second bore, and may define a spherical bearing and a spherical tip. The collar defines an axial bore where the collar is positionable in the first bore such that a portion of the drive shaft is disposed within the axial bore.

CROSS-REFERENCE TO RELATED APPLICATION

N/A

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

N/A

FIELD OF THE INVENTION

The present invention relates to dental instruments, and moreparticularly to dental prophylaxis devices.

BACKGROUND OF THE INVENTION

Dental prophylaxis angles, generally referred to as “prophy angles,” arecommonly used dental instruments providing rotation for dental toolssuch as brushes, prophy cups, or other receptacles used in polishingteeth. A prophy angle typically includes a housing having a neck and ahead portion extending at approximately a 90° angle to the neck, whichincreases the ability of a dentist to reach various surfaces of theteeth of a patient. A drive shaft can be located within the housing andattached to a driven gear in the head of the prophy angle. Prophy anglesare generally affixed to a handpiece, which connects the prophy angle toa drive source, thereby enabling a rotating motion of the drive shaftand driven gear of the prophy angle and any affixed dental tool.

Prophy angles are commonly manufactured from lightweight plastic to makethem disposable and thereby increasing overall sterility in the dentalenvironment. One drawback of these current instruments is that they areoften cumbersome to assemble and may contain a myriad of loosely fittingparts. For example, prior prophy angles have included a two-piecehousing which must be mated together prior to use to enclose the innercomponents of the angle. During use of the prophy angle, the housing mayexperience increased strain when in contact with the teeth of a patient,and cause the seams in the housing to separate and expose the innercomponents of the angle. Such separation in the housing may result in aspacing apart or separation of the internal gears of the angle,potentially leading to failure of the device.

In addition to concerns regarding housing integrity, the drive shaft anddriven gear of an angle may experience some displacement during use ofthe prophy angle. As the angle is being used, the drive shaft mayexcessively move forward or backward due to an increase in the pressureplaced on the rotating parts, and result either in an increased amountof force between the gear teeth of the drive shaft and the driven gear,or separation of engagement of the gear teeth of the shaft from those ofthe driven gear. Subsequently, this displacement can also lead to apremature malfunction of the prophy angle prior to completing a dentalprocedure.

Furthermore, conventional prophy angles may have a significant amount ofcontact between surfaces of the housing, the drive shaft and the drivengear. Such large, often flat surfaces can generate increasing amounts offriction as the prophy angle is used at higher rates of rotation. Theincreased friction can prevent the prophy angle from reaching thedesired rate of rotation, may cause enhanced wear and tear between theinteracting components, and may generate greater heat, thus making theangle uncomfortable to use.

In light of the above limitations, it would be desirable to provide aprophy angle having a singular housing, where the prophy angle limitsdisplacement of the internal components during use, and further reducesfriction between interacting surfaces.

SUMMARY OF THE INVENTION

The present invention advantageously provides a dental prophylaxis anglehaving a singular housing, a drive shaft, a rotor, and a collar. In oneembodiment, the singular housing can include a first bore, a second borein communication with the first bore at a substantial angle thereto, anda third bore coaxial with the second bore. The housing may furtherdefine an annular groove and a first shoulder, where the annular grooveand the first shoulder are disposed about the first bore. In addition,the housing includes a plurality of rotor bearing elements. The driveshaft is positionable in the first bore, with the drive shaft having apost defining a spherical depression.

The prophy angle also provides a rotor positionable in the second boreof the housing, with the rotor defining a spherical bearing and aspherical tip. The rotor may also include a flange that covers asubstantial portion of the second bore when the rotor is positioned inthe second bore. The collar defines an axial bore, a first annular walldisposed about the collar, and a second shoulder also disposed about thecollar. Moreover, the collar is positionable in the first bore of thehousing such that a portion of the drive shaft is disposed within theaxial bore, the annular wall is received by the annular groove of thehousing, and the second shoulder of the collar abuts the first shoulderof the housing.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present invention, and theattendant advantages and features thereof, will be more readilyunderstood by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings wherein:

FIG. 1 shows a top view of a housing in accordance with the presentinvention;

FIG. 2 illustrates a side view of a housing in accordance with thepresent invention;

FIG. 3 depicts a rotor in accordance with the present invention;

FIG. 4 shows a side view of a drive element in accordance with thepresent invention;

FIG. 5 illustrates an angled view of a drive element in accordance withthe present invention;

FIG. 6 depicts a side view of a drive element in accordance with thepresent invention;

FIG. 7 illustrates a collar in accordance with the present invention;

FIG. 8 shows an assembly view of a prophy angle in accordance with thepresent invention; and

FIG. 9 shows an assembled prophy angle in accordance with the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

In an exemplary embodiment, the present invention provides a dentalprophylaxis angle having a singular housing 10, a drive shaft 12, arotor 14, and a collar 16. FIGS. 1 and 2 illustrate the singular housing10 as a one-piece element which defines a first bore 18 extendingthrough a length of the housing 10. A second bore 20 is in communicationwith and extends from the first bore 18 at a substantially perpendicularangle. The housing 10 further defines an annular groove 22circumscribing a portion of the first bore 18, and a housing shoulder 24disposed about a portion of the first bore 18 where the first bore 18decreases in diameter.

A plurality of rotor bearing elements 26 is radially positioned withinthe second bore 20. Each rotor bearing element 26 includes an upperbearing surface 28, as well as having a spherical recess 30 on a surfaceof the bearing element that is substantially perpendicular to the upperbearing surface 28. In addition, the housing 10 includes a third bore 32that is substantially coaxial with the second bore 20, yet having adiameter substantially less then the diameter of the second bore 20. Thehousing 10 can be constructed from a variety of available plasticshaving sufficient rigidity to apply pressure to a patient's teeth, whileremaining flexible enough to receive the internal components of theprophy angle.

As shown in FIG. 3, the rotor 14 includes a button 34 disposed at oneend, to provide, e.g., attachment of a prophy cup (not shown). Thebutton 34 may include additional protrusions to accommodate a specificprophy cup, but is not limited to a specific shape or orientation. Therotor 14 further includes a radially-extending flange 36, a plurality ofdriven gear teeth 38, and an intermediate disc 40 radially disposedabout a center axis of the rotor 14. Moreover, a spherical bearing 42 isincluded along a length of the rotor 14, in addition to a spherical tip44 at an end of the rotor 14 opposite the button 34.

In FIGS. 4 through 6, the drive shaft 12 is shown as an elongate bodyhaving a plurality of drive gear teeth 46 disposed at one end. A post 48extends shortly beyond the plurality of drive gears 46, with the post 48having a spherical depression 50 on an end surface.

Now referring to FIG. 7, the present invention includes the collar 16,where the collar 16 defines an axial bore 52 extending throughout thelength of the collar 16. The collar 16 also includes a protruding firstannular wall 54 circumscribing a portion of the collar 16 proximate afirst end of the collar 16. A second annular wall 56 circles the axialbore 52 at a second end surface opposite the first end of the collar 16.Both the first and second annular walls may include semi-circular crosssections, e.g., the protruding walls may have rounded surfaces. Inaddition, the collar 16 defines a collar shoulder 58 disposed about aportion of the collar 16 where the exterior diameter of the collar 16decreases.

As shown in FIG. 8, the prophy angle of the present invention is shownin an exploded assembly view to illustrate the placement and interactionof the components. In this embodiment, the rotor 14 is positioned withinthe second bore 20 of the singular housing 10 with the spherical tip 44of the rotor 14 extending downward into the third bore 32 of the housing10. Because of the spherical nature of the rotor 14 tip, there isminimal contact between the rotor 14 and the lower surface of the thirdbore 32 as compared to a traditional tip having a flat surface. As such,friction between the spherical tip 44 and the housing 10 is reducedsignificantly at this contact point. Moreover, during use, the sphericaltip 44 acts to transmit high thrust loads experienced by the rotor 14 tothe housing 10, thereby reducing the loads experienced between themeshed gears of the rotor 14 and the drive shaft 12.

The spherical bearing 42 of the rotor 14 is received by the sphericalrecess 30 of each of the plurality of rotor bearing elements 26, withthe intermediate disc 40 being located proximate to the upper bearingsurface 28 of each of the plurality of rotor bearing elements 26. Ofnote, it is not necessary that the curvature of the spherical bearing orthe curvature of the spherical recesses are indeed substantiallyspherical. Rather, it is intended that the curvature of the sphericalbearing is substantially similar to the curvature of the recess in therotor bearing elements, whether the curved surfaces are preciselyspherical, ovoidal, elliptical or otherwise.

The flange 36 of the rotor 14 rests over the opening of the second bore20, effectively preventing any debris from entering the interior of thehousing 10, which could potentially interfere with the subsequentoperation of the prophy angle, while the button 34 for a prophy cup (notshown) remains exposed to the exterior of the housing 10.

Subsequent to the placement of the rotor 14, the drive shaft 12 isinserted into the first bore 18 of the housing 10 such that theplurality of drive gear teeth 46 of the drive shaft 12 engages theplurality of driven gear teeth 38 of the rotor 14. In addition, thespherical depression 50 on the post 48 of the drive shaft 12 abuts thespherical bearing 42 of the rotor 14. While in general operation, thecontact between the spherical depression 50 of the drive shaft 12 andthe spherical bearing 42 of the rotor 14 may be minimal. However, shouldthe drive shaft 12 experience any displacement or increased pressureagainst the rotor 14, the rotor 14 will transmit the additional force tothe housing 10 through the spherical recesses 30 of the plurality ofrotor bearing elements 26. By transferring the force to the housing 10,the likelihood that the increased force will cause the gears of thedrive shaft 12 and the rotor 14 to seize is significantly reduced.

Next, the collar 16 is positioned in the second bore 20 of the housing10 such that a portion of the drive shaft 12 is located within the axialbore 52 of the collar 16. The collar 16 is placed within the housing 10and moved towards the direction of the rotor 14 until the collarshoulder 58 abuts the housing shoulder 24. Moreover, the second annularwall 56 of the collar 16 abuts an underside of the plurality of drivegear teeth at a rear shoulder, providing a rounded bearing surface ofthe collar 16 in contact with the drive shaft 12. The rounded surface ofthe second annular wall 56 reduces the contact area between the collar16 and the drive shaft 12, thereby reducing friction as compared totraditional flat contact surface areas.

In this position, the first annular wall 54 of the collar 16 coupleswith the annular groove 22 of the housing 10, thereby securing thecollar 16 in the housing 10. As a result, the collar 16 secures thedrive shaft 12 in engagement with the rotor 14, which is furthersupported and secured by the plurality of rotor bearing elements 26 inthe second bore 20 of the housing 10. These features of the prophy anglesignificantly reduce and may altogether prevent any displacement of thedrive shaft 12 or rotor 14 while the prophy angle is being used.

The prophy angle of the present invention provides an easily assembleddental device having features which secure the inner components againstdisplacement during use, as well as providing numerous rounded surfaceswhich reduce friction experienced between moving parts by reducing thecontacting surface areas.

It will be appreciated by persons skilled in the art that the presentinvention is not limited to what has been particularly shown anddescribed herein above. In addition, unless mention was made above tothe contrary, it should be noted that all of the accompanying drawingsare not to scale. A variety of modifications and variations are possiblein light of the above teachings without departing from the scope andspirit of the invention, which is limited only by the following claims.

1. A dental prophylaxis angle, comprising: a housing defining a firstbore and a second bore in communication with the first bore, a driveshaft having a head and positionable in the first bore; a rotorpositionable in the second bore; and a collar defining an axial boretherethrough and positionable within the first bore, the collar includesan outwardly-facing first annular wall having a rounded bearing surface,wherein the drive shaft is positioned, at least in part, within theaxial bore, and the rounded bearing surface of the first annular wallengages a rear shoulder of the head of the drive shaft.